Drafting machine



March 6,1945. L. KETTING 2,370,971

DRAFTING MACHINE Filed June 3, 1942 s Shets-Sheet 1 INVENTOR L'E/VDEAT lfETT/NG ATTORNEYS March 6, 1945. I I KETTING 2,370,971

' DRAFTING MACHINE Filed June 5, 1942 3 Sheets-Sheet 2 IN VENTOR. LEEA/DERT lfE'TT/NG ATTORNEYS March 6, 1945. L. KET' l'lNG DEAF-TING MACHINE Filed June 3, 1942 3 Sheets-Sheet 3 LEENDERT KETWIVG ATTORNEYS Patented Mar. 6, 1945 DRAFTING MACHINE LeendertK etting, Secaucus, N. J., assignor to Keufiel & Esser Company, Hoboken, N. 1., a

corporation of New Jersey Application June 3, 1942, Serial No. 445,540

19 Claims.

tion drafting devices of the kind in which the several tools which the .draftsman handles most frequently are embodied, in principle, in ,one

unit to obviate the necessity of a draftsman reaching about for a required tool and thereby enabling the draftsman to keep his attentionconcentrated directly upon the drawing.

Drafting devices'of this character arecommon in which adjacent endsof two arms are pivoted together, the free end of one arm being anchored tothe remote side of adraftingboard while the free end of the other arm is provided with a head comprising a protractor and straight-edges which are in fixed angular relation and move about the 5 center of the protractor as an axis. Such straight-edges have heretofore been so associated with the protractor as to be set and locked at any angle of the protractor or tobe automatically locked at predetermined intervals. However, the instrumentalities effecting the setting of the straight-edges with respect to readings on the protractor have been characterized by dii'ficulty in the manual actuation of the locking device because of its inaccessibility.

One object of the present invention is a drafting device of the character described, wherein actuating means of the locking devices for the straight-edges are readily accessible for manipulation by the thumb or a fingerwithout moving the hand from the actuating knob on the protractor head. a

It is also an object ofthe invention to effect the releasing oflatching means for the straightedges by a movement of the hand of the oper-.

ator which is, in effect, an exaggerated movement of the hand in grasping the knob.

, The invention also has for one of its objects locking and releasing mechanism for the protractor which may conveniently be actuated-by provided on the knob, which is movable downwardly at any point about its, periphery to unlatch the straight-edges and permit them tobe moved freely to any angular position but which,

on release, will effect locking of the protractor; ,at the nearest even predetermined position.

Another object of the invention is to return the disc on the knob to initial position wheneve itis released by the operator. Accordingly, power is stored in power storingdevices when the disc 1 This invention relates generallyto parallel mo- L is moved from' initial position and which is utilized to return the disc.. V I

The invention further seeks an instrumentality transferring the substantially vertical movement of the thumb or finger actuated device to the latching devices for the straight edges to simplify assembly and to'avoid the necessity for interlocking lever arms and other movement transferring devices.

The invention also resides in the details of construction by which the drafting device is made practical from the standpoint of ease, simplicity and convenience in manufacture and assembly as well as durability and facility in use.

, Ihese and other objects of the invention and the means for their attainment will be more apparent from the following detailed description, taken in connection with the accompanying drawings illustrating one embodiment by which the invention may be realized, and in which:

Figure 1 is a diagrammatic view showing the drafting machine mounted on a drawing table; Figure 2 is a viewshowing the head of the drafting device of this invention in vertical section,

Figure 3 is a transverse view taken in the planeindicated by the line 3-3 of Figure 2, looking in the direction of the arrows; and

Figure 4 is a fragmentary plan view taken in the plane 4-4 of Figure '2.

Referring first to'Figure 1, there is illustrated a typicalfendless band and pulley type of drafting machine which comprises a pair of arms 6,

7 each comprised of tubes 8 within which an end-- less band 9 in each arm travels. The adjacent ends ,of the arms are pivoted together, asfat Ill. The free end of one arm is anchored, as at l2, to theside' of a drafting board, l3 while the free end of the other arm' is provided with a supporting head M comprising the knob or handle IS, a protractor I8 and frame means 20 supporting the straight-edges 22. Obviously the arms may assume any convenient structural shape and theinverition is applicable to types of parallel motion mechanisms other than the wheel and band type illustrated.

of a retaining ring 36 threaded to the upper end of the hub 35. Thus-the pulley 28 is free to re- 'tate within the frame portion 24 of the head which pin 84 is carried by the end of the slide 86 slidable in a slot or the equivalent 88 formed in the frame 20 and terminating proximate the lower end of the pivot pin 44. In order to hold the straight-edge at points intermediate the registering position of the notches, a lock member I is provided which, since it is rarely used, is carried,in=the illustratedembodiment, at a low point as onthe frame 20. Any-:convenien t clampin the cylindrical hub of the pulley is disposed- I a sleeve 44 functioning as a pivot pin and hav ing its upper end of reduced diameter;-as-indi-* cated at 46, so that a shoulder 48is provided subvstantially flush with the upperz surfiacemi the pulley hub 35. The sleeve 44 is secured to, as:

by being made integral with, a plate-like bottom portion to which the straight=tlgesiipfiortihg frame 20 is secured as by'the screws 52.-: V

, The knob I6 is secured to the pivot pin 44 so that rotation "6f the linob -lfi' wi-ll ma te-the straight-edge supporting rrame'z't wheneve that frame is released frbm ti-ie pulley by disengaging a" common 'type offlatc'h men ber- 54 from the todthed latching plate 40 as will be 4 understood; The kn'ob I6fis pperatively' ccnnected 'with the pivot pin in the following manner: h I e knob IB is recessed; as-et andi 'eceives a generally cylindrical or cup shapedknob sup portir'i'g frame in'eniber IMP-f6)[comprised of the cylindrical or annular wall and a 'bot tcrn' wall 62 which re illustrated as extending Beyond the circumferential margin'pf "the walltll as a bevelled flange 631:0 serve as v a 7 stop foi a manually actuatable deviee 689 10 controlling the pawl 54 as hereinafter described. The upper erid'"46 er the tubular ivetr pint; is ii'e 'm ppsitionby a nut 12 threaded en the upper end of the pivot member and i'seatmgo the bdttom'wall' are:

the cup-shaped membe to retain it against the spacing ring on shbulder 4 8; Thus the pulley 28 and knob frame60 -62fareheld in assembly on the pivetjmmber 44 'py'mea sj of the "disclike pcitiefi 50 at its lewerend'aii'cl the niit -l'ike member I2 at its upper end. The knob I6 issecured to the wan 60 'as byaserewM whereby rotary movement "of 'the knob and with it," the frame member 60'; 62"will turnithepivo't pin 44 and thereby the metemmee supporting 'jrame t I meinerslet i time as.

10 portion-I I5 entersa groove or" passage I I1 formed ing lever or locking means may be provided with- 1' in the purview of this invention and no further discussion thereof is necessary.

Beneath the slide 86 is a lever I02, I04 pivoted to the irameizmas at I05, and connected to'the sl ide ;-,86 withvprovision for lost motion by a pin The free end I04 of the lever I02, I04 is positioned proximate the manually actuatable device I00, which is used to bore l2 extending from the up er end to a point,

conveniently; in -substantially the plane er the disc-portion er thepulley 28." From that peiiit, the-bore is manned downwardly andoutward'ly, "as at us; td'the periphry ersiae portion er the enlargement H0 inregister withthe ihiier end of the slide 86 which conveniently rnaybe constricted td substantiallythe'diaineter of the bore II2,' I13, as shown at 'I I5. The constricted in a block H9 secured as by the screws to l the frame member 20. The passage II! is in register with thebore II3'and forms a continuation thereof. Withinthe axial portion II2 "of the bore, a rod-likbltihg'er I22 is disposed which is conveniently previde'u vvith'a curved'upper'end, in this instance represented by a ballbe'ar'ing I24 seated iii a hemispherical recess I26 in the the knob'. As "shownjthe manually actuatable.

device takes the form of: a disc which; as illustrated, is comprised of an'upwardly convex central portion '66 end a finger 'erlgajgeable annu1ar concave'rimportiqn 69; Betweeii'the'cchvex and concave portions the 'dise' is 'ior'me'tl with an annular row of slots 10." v e I The cooperating latching member is" shown in greater detail in Figure 3 as n en n d" shaped Y lever 54 formed with a-detent "I6 'atitsorie end,

whichis' so shaped as to enter-into andpositioh;

itself n che of recesses I8 "of latch plate 40. The other extremity (ii the pawl54 i's'formed with an aperture Bil-rot reception'on 'arpir'i $2 m t t se te e 'evi rti teen 20;" The lever '54 is urged toward the latching atent by the engagement-6r a pm 84 therewith,

ehar the plunger 122.] The; plunger 1'22 terminates-short ofthe lower end of the axial bore I I2 and the remainder'ef the axial bore and the inclined bore H3 is filled with balls I28, saypf steel, which are prevented from escaping by end'I I5 'of the reciprocable'memhr 861' It will be readily'apprec iated, thereforeythat wheneverthe plunger I22 is depressemthe' series the I of balls-l2 8 will be rereeu downwardly in the balls I28 are shown between'theipliihger lzz' ana r passage II2,' II3 sressingeeemst the erid II5 of the reciprbcable member and displacing it to'the right, as viewed in Figiire2fto actuate I the latch 54 against the reactidii of the spring I08; 'Obvi0u'sly,.whi1e elements such as steel the reciproeable member 86-, any elements transmitting the fiertical rn'ovement' of the plate 68, 10"td thehoriz'ontally' movable member '86 in order t6 actuate the l'atcl'1'54 are within the purview ofthe-invehtioh. I The jknob frame portion 60 "is conveniently providedyvith an annular series of slots 1 30 es:- tending conviiiritlyyas shown'in Figure 2, the f ullldepth ofth Wall 60, that is; to the plane r'tne u per uiffae or the bctt'om member-t2. These 'slc'ts' 13"0' "are j'p fi'a-bly *tniee'itrhtimber eta iii the iiibdifieatioiishevtndefine 'threeedual wall segments I32 preferably equally spaced from one another. The slots III in the manually actuatable device 68, III are so shaped as to loosely receive or fit over the segmental wall portions I32. 3 Disc 68, I is illustrated as supported with the convex portion 68 thereof normally. in-spaced relation to the upper end of the plunger I22or to the ball I24 seated in the end thereof by a helical spring I34 seated on the bottom 62 of the frame 6062 and engaging the bottom of the convex portion 68 of the disc. The helical spring I34 is conveniently of slightly greater diameter than the nut I2 but is retained against substantial displacement by the nut. I v

The disc 68, His retained in operative'position on the frame 50, 62 by a depending annular inner flange I38illustrated as formed by anannular recess I38 in the knob, This flange I38 is concentric with the wall segments I32 and conveniently is that portion of the knob which is formed with the recess 56. The cylindrical wall of the recess 56 is shown as rabbeted, as-at I40, to receive the wall segments. The annular depending flange I38 or its equivalent servesnot only to position the disc BIL-69in a transverse plane when acted upon by the spring I34 but also serves as a fulcrum about whichthe disc 68-69 may rock when any point on its periphery on an opposite side of the convex portion is depressed. Obviously, the spring I34 can be dispensed with, the disc 68, 63 then resting on the bearing I24.

By means of the disc 6869-, a draftsman may release the straight-edges by a finger or the thumb of the hand which grasps the knob I6 and without displacing the 'handin any respect on the knob from whatever relative position on the knob he normally grasps the same and may do this with whatever finger'or thumb he so ,desires. He merely presses downwardly with the end of the. selected finger orthe thumb at any point on the periphery or within the depressed annular rim portion 89 to force downwardly that portion of the disc to cause the diametrically opposite portion of the disc 68, 69 to pivot or rock about the depending flange I38 as a. fillcrum. By this manipulation of the disc the central portion 68 of the disc is caused to move downwardly into engagement with and depresses the plunger I22 to advance thelink 86 and release the latch 54. Obviously, when pressure on the disc 68, 69 is relieved, the spring I34 returns the disc to initial or normal position and the spring I08 tends to return the latch to latching position and the elements. I22, I28 to initial position. Release of the pawl iseffected in this manner by downward movement of any portion of the periphery of the disc caused by downward pressure at any one point or at all points on its peripheral portion.

The knob I6 may be undercut as at I4I about its lowermost outer periphery which not only affords a convenient hand grasp in lifting the head but permits the insertion of one or more digits between the knob and the discas by merely exinsufficient room for. the digits inthis space the insertion of the digit .or digits will displace the disc downwardly, say, on a portion of or. .on its a 3 entire periphery, and thus cause the plunger I22 to be depressed. I

I Various modifications will occur to those skilled in the art in the composition, configuration and disposition of the component elements going 'to make up the inventionas a whole as well as in the selection and combination of features toaccomplish the results sought, and no limitation is intendedby the phraseology of the foregoing description or illustrations in the accompanying drawings, except as indicated in the appended claims.

What is claimed is: I 1. In a drafting machine, in combination, means fixed in orientation, a straight-edge supporting frame, means to latch said frame to said means fixed in orientation, means mounting said straight-edge supporting frame for rotary movement, a cup-shaped frame carried by the last named means, a handle carried by the cupshaped frame in spaced relation to the bottom thereof, reciprocable means to actuate'the latch means, said mounting means being formedwith a passage whereof one end is in register with the reciprocable means, a plurality of elements disposed therein and protruding from an end. of the passage, a disc means carried by the frame below the handle and engageable with one of the elements and means between the disc and the bottom of the frame normally urging the disc away from an element of the mounting means.

2. In a drafting machine, in combination, means fixed in orientation, a straight-edge supporting frame, means to latch said frame to said means fixed in orientatiommeans mounting said provision for reciprocation and an element ,pro-

truding from at least the upper end of the passage, a disc carried by the frame below the handle mounted for tilting movement between the frame and the handle, said disc engaging a reciprocating element protruding from the upper end of the passage whereby tilting of the disccauses the series of elements to protrude from the passageand actuate the reciprocable latch-actuating means.

3.In a drafting machine, in combination, mean fixed in orientation, a straight-edge supporting frame, means to latch said frame 'to said means fixed in orientation, means mounting said straight-edge supporting frame for rotarymovement, a cup-shaped frame carried by the last named means, a handle carried by the cupshaped frame in spaced relation to the bottom thereof, reciprocablemeans to actuate the latch means, said mounting means being formed with a passage extending axially from its upper end and then inclined to its lowermost periphery to register with the reciprocable means, a plurality of elements disposed therein and protruding from anend of the passage, a disc carried by the frame below the handle and engageable with an element protruding from the axially extending passage. 4. In a drafting machine, in combination, means fixed in orientation, a straight-edge supportingxframa'means to latchisaid: frameto "said a means fixed in orientation, meansmountingsaid straight=edgesupporting frame for rotary movemenai acup=shaped frame carried by: the last named-means,- a handle carried by the cup shaped frame linrspaced relation to the bottom thereof;

reeipro'cable means to actuate the latch'rneans, said mounting means being formed with a pas sage'extendingaxially from its upper end and then-inclined tola lower periphery in register withithe re'ciproc'able means, a plunger .:in- -the asrzme'n axial portion of the passage, a plurality .efaelements disposed in the, passage below the plunger, saidplunger protruding from the end of the passage,:'and adisc carried bytthe frame b'elowthe handle and engageable with the plunger. 1 15; 'In a v:drarting machine, in combination,

, means fixedinorientation, a straight-edge sup portingframe, means to latch said frame to said means fixedin'orientation, m'eansmounting said str'aighteedge supportingframe for rotary move mentiaaframe'carried by the last named means I means fixed in orientation, a straight-edge supporting 'fr-ameinean to latch said frame to said means fixed inorientati'on, means mounting said straight-edge supporting frame for' rotary moveinent, aframe carried by the last named means and formed with spaced peripheral'wallportions,

a handle carriedby the last named frame, re-

c'iprceable means to actuate the latch means, said'mountingmeansbeing formed with a pas- .sage .extending-from-its-upper. end to its lower .inost periphery in'register with the reciprocable means, means disposed therein and protruding froman end of the passage, and a manual1y engageable disc formed with slots receivingthe :framewall portions and carried by the frame below'the' handle and engageable with one :of V

the said; means. a 1 n7. In a drafting machine, in' combination,

means: fixed. in orientation, a straight-'edge' sup porting frame, means to latch "said frame to said means fixed in orientation, means mounting :said straight-edge supporting frame for rotary movement, a cupe'shape'd :frame'carried by the last :riamedi-means and whereof the wall is formed with a plurality of slots defining an annular'row' of .spa'ce'd wallportions, a handle carried by the w cup-shaped frame in spaced relation to the bot tom of .the slots,. reciprocable means to actuate :the...latch means, said mounting means being formed with a passage extending from: its upper end to-its lowermost periphery in'register with the reciprocable means, a plurality of elements clisposed'therein and protruding from an end :of the-passage, a disc formed withan annular row :ofslots receiving said'wall portions and'disposed below the handle for engagement with a protruding elementfor actuating of the latch means.

, -8.-=In-"a drafting machine, in combination,

means fixed in orientation, a straight edge supportingframe, 'means to latch said frame to said means fixedin orientation," means mounting said 4 straight edge supporting: frame forl: rotary, movement, a framecarr-i'ed "by the last named means having a wall formed with ran annulanrowof spacedwall/portions, a handle carried by the last named frame above the bottom thereof, re ciprocable means to actuate the latchmeans, said: mounting means being zformed with a 'pas sage extending from its upper end to its iower= most periphery in register with. the reeiprocable means, a pluralityof element's disposed therei'n and protruding froman 'endiof'zthe passage, and a fd-isc formed with an annular row of slots re:- ceiving the wall portions and disposed below the handle. v

-9.-In a-drafting machine: in combination, means fixed-in, orientation, a straight-edge sup-:- porting frame, means to latclr'said-frame tosaid meansvnxed in orientatiommean's mounting said straight-edge supporting; frame for rotary movementpa cup shaped frame carried by .l-the last named means, a handle-carried by the cup shaped -frame in spacedrelation to the-bottom thereof, reciproc'able means to actuate the latch means, said ,mounting means beingiformedwith ;a-:passage extending from its upper end "to its lowermost periphery in register with thereciprocable means; a plurality of elements disposed therein and-protruding -from1an' end or the: .passage, and a disc carried by :the cup-shaped frame, means loosely. mounting, saiddiSc- *on said Irame whereby "said: disc; may "be wobbled below the handle whereby an edge of the disc maybendapressed and a: disc portion depressed to displace the elements in the apassageaand actuate-the reciprocable means; 7 v

IOVInU a drafting -.maehine, in combination, means fixed-in orientationa straighaedge sup.- porting frame, mean to latch said frame: to: said means fixedv in orientation m'eans mounting said straight-edge supportingframe forrotary .move

ment a frame carriedby the last'named means,

a handle carried by theilastnamed frame, reciprocable' means to actuate the latch means,

said mounting means, being formed with a passage extending from its upper end to-itg lowermost periphery. in. register with the reciprocable means, a a plurality of. .elementsdisposed therein andprotruding from-at least one endo-f-the passage, a disc carried..by -thelframebelow the handle andio'rmed withaconvex=centralportion adapted to engageanddepressan element,.and

a ncave'perrpherai portion adapted. to be depressed by}; digitof the hand gras ing the handle,

111" In- "a drafting machine, in command-n, A

meansifiiced orientation, a straight-edge supporting rramemeens to lathisaid frame to said means fixed in orientation, a" pivot pin must: we said straight-edge supporting frame id'r rotary-movementya cup=shapen frame carried by the pivot pin and having a stop flange-ahanme carried by the cupe'sha'ped frame in spacearelation to the stop flange; a reciprocable link-ti:

actuaa the hitch means;- said pivot in Being formed wane passage extending "from itsupper endro its mwerm-osr eripnery m registen'with 'therecipfoca'bie" means, a piu'ramy'or' elements diSposed-tHi'ein'and protruding-tram arr-end 6f the passage,-sa aisccarried by th "'cup snaped frame between Eh h'afll'le and: the *tdp range and spring means between Jtli disk? and themattom zof the icup-shapedlfra'm'e.

12.1 In. a drafting. rmachin'e, in: combination, means fixed :in orientation-,l a 's'straight-edgek-sup- "portingframepmeans te'latch said frame to said means fixed in orientation, a pivot pin mounting said straight-edge supporting frame for rotary movement, a cup-shaped frame carried by the pivot pin and having a stop flange formed with a downwardly and outwardly inclined upper surface, a handle carried by the cup-shaped frame in spaced relation to the stop flange, a reciprocable link to actuate the latch means, said pivot pin being formed with a passage extending from its upper end 11; its lowermost periphery in register with the reciprocable means, a plurality of element disposed therein and'protruding from at least one end of th passage, a disc carried i by the cup-shaped frame between the handle and the stop flange, and spring means between the disc and the bottom of the cup-shaped frame.

13. In a drafting machine, in combination, means fixed in orientation, a straight-edge supporting frame, means to latch said frame to said means fixed in orientation, a pivot pin mounting said straight-edge supporting frame for rotary movement, a cup-shaped frame carried by the pivot pin, a handle carried by the cup-shaped frame and having a depending flange surrounding the frame, a reciprocable link to actuate the latch means, spring means urging'the link to latch engaged position, said pivot pin being formed with a passage extending from its upper end to its lowermost periphery in register with the reciprocable means, a plurality of elements disposed therein and protruding from an end of the passage, a disc means to loosely carry said disc on the cup-shaped frame below the depending flange of the handle whereby said disc is tiltable about said flange as a fulcrum to engage and depress an element to actuate the latch.

14. In a drafting machine, in combination, means fixed in orientation, a straight-edge supporting frame, means to latch said frame to said means fixed in orientation, a pivot pin mounting saidstraight-edge supporting frame for rotary movement, a cup-shaped frame carried by the pivot pin, a handle carried by the cup-shaped frame, a reciprocable link to actuate the latch means, said pivot pin being formed with a passage extending axially from its upper end to an intermediate point and from thence at an angle frame on the pivot pin, reciprocable means to I actuate the latch means, said pivot pin being formed with a passage extending axially from its upper end to an intermediate point and from thence at an angle to its lowermost periphery'in register with the reciprocable means, a plunger element in the axial portion of the bore, a plurality of ball elements disposed in the passage below the plunger element, a ball seated in the end of the plunger, the plunger protruding from the end of the passage, and a disc carried by the frame below the handle to engage the ball on the end of the plunger and depress the same to actuate the latch means when the disc is maniputo its lowermost periphery to register with the reciprocable means, a plurality of elements disposed in the passage and protruding from an end of the passage, a disc, the cup-shaped frame comprising means below the handle to loosely support said disc whereby said disc is depressible to displace the elements and thereby actuate the reciprocable link.

15. In a drafting machine, in combination, means fixed in orientation, a straight-edge supporting frame, means to latch said frame to said means fixed in orientation, a pivot pin mounting said straight-edge supporting frame for rotary movement, a frame carried by the pivot pin, a

handle carried by the last named frame, reciprocable means to actuate the latch means, said pivot pin being formed with a passage extending axially from its upper end to an intermediate point and from thence at an angle to its lowermost periphery in register with the reciprocable means, a plunger element in the axial portion of the bore, a plurality of ball elements disposed in the passage below the plunger element, at least one of said elements normally protruding from the ends of the passage, respectively, and

a disc carried by the frame below the handle I lated.

17. In a drafting machine, means fixed in orientation, a straight-edge supporting frame, latching means to latch said frame to said means fixed in orientation, a handle fixed to said straight-edge supporting frame for rotating said straight-edge supporting frame about a vertical axis when the latching means is released, said handle comprising downwardly facing circumferentially disposed fulcrum points, a disclike member below the top of said handle, operative connections between said disc-like member and said latching means, and mean mounting said disc-like member for pivotal movement about said fulcrum points respectively to actuate said latching means through said operative connections.

. 18. In a drafting machine, mean fixed in orientation, a straight-edge supporting frame, latching means to latch said frame to said means fixed in orientation, a pivot pin mounting said straight-edge supporting frame for rotary movemerit about a vertical axis, a cylindrical member formed with vertical slots and mounted on said pivot pin, a relatively fiat member carried at an intermediate horizontal plane of said cylindrical member having spokes extending outwardly through said slots, a knob mounted on said cylindrical member closing the upper ends of said slots and about which the flat member may pivot and means actuated by said fiat member in its pivotal movement to actuate said latching means.

19. In a drafting machine, means fixed in orientation, a straight-edge supporting frame latching means to latch said frame to said means fixed in orientation, means fixed to said straightedge supporting frame for rotating said straightedge supporting frame about a vertical axis when the latching means is released, said means for rotating comprising a pivot pin, a member operatively connected with said means for rotating, means pivotally mounting said member for move- .ment selectively about a plurality of different horizontal axes lying in the same transverse plane, and means responsive to pivotal movement of said pivotally mounted member about any of said axes to actuate said latching means and release the frame for rotation.

LEENDERT KETTING. 

